In the process for fabricating electronic, in particular optoelectronic, components, there is a need to store, to handle and to transport individual chips. Transport steps may be effected both in the course of production and quality control and on route to the customer. Depending on their design, chips have parts and surfaces of different sensitivity and can thus be damaged in different ways during these individual process steps. By way of example, high-power laser diodes have sensitive mirror facets which must not be damaged nor contaminated in the course of transport during the final inspection steps after singulation or during transport to the customer. Neither cleaning nor photolithographic or mechanical rework can be effected in the singulated state.
Chips are conventionally held or transported for example in so-called gel packs. In this case, a special plastic functions as an adhesion medium. Individual chips are deposited on said adhesion medium, to which they adhere even in the event of strong vibrations. They do not fall out of the receptacle and scarcely change their position. The adhesion film is situated on the underside of the bottom of a plastic box. The chips are removed on a vacuum station. Here, parts of the adhering film are sucked into the cavities of the grid structure situated underneath, thereby reducing the effective adhesion area. Consequently, such vacuum stations have to be present wherever chips are intended to be removed from the receptacle, that is to say also on the customer's premises. Reuse of the gel packs is critical since the residues and contaminations of the plastic can reduce the long-term stability of chips stored in such receptacles.
A further possibility for chip storage and chip transport consists in so-called waffle packs, which dispense with an adhering gel layer. In this case, cavities are present in a plastic box, into which the individual chips can be placed.
When using plastic-containing holding receptacles for chips, there is the problem that individual constituents of the plastics can outgas, which may result in contamination of individual parts of the chips. Thus, the mirror property of a dielectric mirror which functions according to the principle of light refraction at layers having different refractive indexes and thus relies on high material purity may be altered and the output power of a component may thus be reduced.
Furthermore, there is the problem that the chips have a relatively large freedom of movement within the cavities, so that, during transport, there is the risk of chips standing up, tilting or striking the cover of the receptacle with their top side, as a result of which damage may arise.